Study of the Multi-Directional Intraoral X-Ray System for Clinical Diagnosis of Dental Caries

Cho, Samju,Mah, Yon-Joo,Kim, Nahyun,Choi, Seulki,Lee, Rena,Choi, Byung-Joon,Pang, Eun-Kyoung 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.5

Statistical process control analysis for patient quality assurance of intensity modulated radiation therapy

Lee, Rena,Kim, Kyubo,Cho, Samju,Lim, Sangwook,Lee, Suk,Shim, Jang Bo,Huh, Hyun Do,Lee, Sang Hoon,Ahn, Sohyun 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol. No.

<P>This study applied statistical process control to set and verify the quality assurances (QA) tolerance standard for our hospital's characteristics with the criteria standards that are applied to all the treatment sites with this analysis. Gamma test factor of delivery quality assurances (DQA) was based on 3%/3 mm. Head and neck, breast, prostate cases of intensity modulated radiation therapy (IMRT) or volumetric arc radiation therapy (VMAT) were selected for the analysis of the QA treatment sites. The numbers of data used in the analysis were 73 and 68 for head and neck patients. Prostate and breast were 49 and 152 by MapCHECK and ArcCHECK respectively. C (p) value of head and neck and prostate QA were above 1.0, C (pml) is 1.53 and 1.71 respectively, which is close to the target value of 100%. C (pml) value of breast (IMRT) was 1.67, data values are close to the target value of 95%. But value of was 0.90, which means that the data values are widely distributed. C (p) and C (pml) of breast VMAT QA were respectively 1.07 and 2.10. This suggests that the VMAT QA has better process capability than the IMRT QA. Consequently, we should pay more attention to planning and QA before treatment for breast Radiotherapy.</P>

Feasibility Study of a Custom-made Film for End-to-End Quality Assurance Test of Robotic Intensity Modulated Radiation Therapy System

Kim, Juhye,Park, Kwangwoo,Yoon, Jeongmin,Lee, Eungman,Cho, Samju,Ahn, Sohyun,Park, Jeongeun,Choi, Wonhoon,Lee, Ho Korean Society of Medical Physics 2016 의학물리 Vol.27 No.4

This paper aims to verify the clinical feasibility of a custom-made film created by a laser cutting tool for End-to-End (E2E) quality assurance in robotic intensity modulated radiation therapy system. The custom-made film was fabricated from the Gafchromic EBT3 film with the size of $8^{{\prime}{\prime}}{\times}10^{{\prime}{\prime}}$ using a drawing that is identical to the shape and scale of the original E2E film. The drawing was created by using a computer aided design program with the image file, which is obtained by scanning original E2E film. Beam delivery and evaluations were respectively performed with the original film and the custom-made film using fixed-cone collimator on three tracking modes: 6D skull (6DS), Xsight spine (XS), and Xsight lung (XL). The differences between total targeting errors of the original and custom-made films were recorded as 0.17 mm, 0.3 mm, and 0.17 mm at 6DS, XS, and XL tracking modes, respectively. This indicates that the custom-made film could yield nearly equivalent results to those of the original E2E film, given the uncertainties caused by distortions during film scanning and vibrations associated with film cutting. By confirming the clinical feasibility of a custom-made film for E2E testing, it can be expected that economic efficiency of the testing will increase accordingly.

Database for Patient Information Management in Radiation Oncology Department

Lim, Sangwook,Kim, Kyubo,Ahn, Sohyun,Lee, Sang Hoon,Lee, Rena,Cho, Samju Korean Society of Medical Physics 2018 의학물리 Vol.29 No.1

The purpose of this study is to build a database of patient information for efficient radiotherapy management. Microsoft Office Access was used to build the database owing to its convenience and compatibility. The most important aspect when building the patient database is to make the input and management of patient information efficient at every step of radiotherapy process. The information input starts from the patient's first visit to the radiation therapy department and ends upon completion of the radiotherapy. The forms for each step of radiotherapy process include the patient information form, the radiotherapy schedule form, the radiotherapy information form, the simulation order form, and the patient history form. Every form is centrically connected to the radiation oncology department's patient information form. A test revealed that the database was found to be efficient in managing patient information at each step. An important benefit of this database is improved efficiency in radiotherapy management. Information on patients who received radiotherapy is stored in a database. This means that this clinical data can be found easily and used in future, which will be helpful in research studies on the radiation oncology department. Benefits such as these will potentially contribute to improved radiotherapy quality.

Pro‐apoptotic Noxa is involved in ablative focal irradiation‐induced lung injury

Kim, Jee‐,Youn,An, Yong‐,Min,Choi, Won Hoon,Kim, Jin‐,Mo,Cho, Samju,Yoo, Byung Rok,Kang, Jeong Wook,Lee, Yun‐,Sil,Lee, Yoon‐,Jin,Cho, Jaeho CAROL DAVILA UNIVERSITY PRESS 2017 JOURNAL OF CELLULAR AND MOLECULAR MEDICINE Vol.21 No.4

<P><B>Abstract</B></P><P>Although lung injury including fibrosis is a well‐documented side effect of lung irradiation, the mechanisms underlying its pathology are poorly understood. X‐rays are known to cause apoptosis in the alveolar epithelial cells of irradiated lungs, which results in fibrosis due to the proliferation and differentiation of fibroblasts and the deposition of collagen. Apoptosis and BH3‐only pro‐apoptotic proteins have been implicated in the pathogenesis of pulmonary fibrosis. Recently, we have established a clinically analogous experimental model that reflects focal high‐dose irradiation of the ipsilateral lung. The goal of this study was to elucidate the mechanism underlying radiation‐induced lung injury based on this model. A radiation dose of 90 Gy was focally delivered to the left lung of C57BL/6 mice for 14 days. About 9 days after irradiation, the mice began to show increased levels of the pro‐apoptotic protein Noxa in the irradiated lung alongside increased apoptosis and fibrosis. Suppression of Noxa expression by small interfering RNA protected cells from radiation‐induced cell death and decreased expression of fibrogenic markers. Furthermore, we showed that reactive oxygen species participate in Noxa‐mediated, radiation‐induced cell death. Taken together, our results show that Noxa is involved in X‐ray‐induced lung injury.</P>

Basic Radiological Characteristics of a Non-Scattering Gel Dosimeter for 3D Dosimetry

Kyung Hwan Chang,Yunseo Ji,Suk Lee,Kwang Hyeon Kim,Dae Sik Yang,Jung Ae Lee,Young Je Park,Won Sup Yoon,Chul Yong Kim,Yuanjie Cao,Samju Cho 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.11

We used a spectrophotometer to compare the dosimetric properties of two non-scattering (radiochromic) gel dosimeters: a non-scattering gel dosimeter developed in-house and a PRESAGETM gel dosimeter. We evaluated the dosimetric characteristics, including spectral absorption, dose linearity, reproducibility, and dose rate dependency of the two gel dosimeters. The non-scattering gel and the PRESAGETM gel dosimeters showed peak sensitivity at wavelengths of 600 nm and 630 nm, respectively. Over a range of doses the best dose linearities of the non-scattering and the PRESAGETM gel dosimeters resulted in R2 values of 0.99 at wavelengths of 600 nm and 630 nm, respectively. The reproducibility and dose-rate dependence of each of the two gel dosimeters were within the range of ±3 %. Our results revealed that the peak sensitivities of the two radiochromic gel dosimeters were significantly different; the in-house non-scattering gel dosimeter demonstrated peak sensitivity at a wavelength of 600 nm while the PRESAGETM gel dosimeter had peak sensitivity at a wavelength of 630 nm. We confirmed that for 3D gel dosimetry, the in-house non-scattering gel dosimeter had a more stable dose response compared with a commercial non-scattering gel dosimeter.

Invivo Dosimetry for Mammography with and without Lead Apron Using the Glass Dosimeters

유수정,임상욱,마선영,서선열,김영재,강영남,금기창,조삼주,Yu, Su-Jeong,Lim, Sangwook,Ma, Sun Young,Seo, Sun-Youl,Kim, Young-Jae,Kang, Young-Nam,Keum, Ki Chang,Cho, Samju Korean Society of Medical Physics 2015 의학물리 Vol.26 No.2

본 연구는 유방촬영술을 시행할 때 유방인접조직의 생체내선량 측정을 통해 방호복 착용의 유용성을 평가하고자 한다. 이를 위해 유방검진을 받는 일반 여성 중 연구의 목적과 방법을 정확히 이해하고 동의한 환자 30명을 대상으로 유방촬영시 유리선량계를 이용하여 측정을 실시 하였다. 유리선량계의 교정값을 구하기 위하여 팬텀(ACR phantom)을 이용하여 촬영 변수중 각각 관전압과 관전류의 중간값(27 kVp, 120 mAs)고정 시 mAs와 kVp를 변화시켜 장치에서 계산된 선량을 얻어 유리선량계 소자의 교정값을 구하였다. 측정 그룹은 방호복을 착용하지 않는 A 그룹과 착용하지 않은 B 그룹으로 나누었다. 생체내 선량측정 특성상 동일한 환자를 대상으로 반복 촬영을 할 수 없음으로 A 그룹은 좌 우 유방촬영에 따라 인접 정상조직의 선량이 차이가 없을 보고자 하였다. B 그룹은 한쪽 유방은 방호복으로 차폐를 하고 다른 쪽 유방은 방호복으로 차폐를 하지 않음으로 그 차이를 보고자 하였다. 인접 정상조직 측정에는 갑상선, 검사반대측 유방, 하복부로 각각의 부위에 유리선량계를 위치시켜 측정하였다. 실험 결과 유방촬영 시 입사표면선량은 A그룹의 경우, 왼쪽유방 상하방향 검사 시 갑상선은 0.0692 mGy, 오른쪽 유방은 0.6790 mGy, 하복부의 선량은 0.0122 mGy로 나타났고, 오른쪽 상하방향 검사 시에는 각각 0.0607 mGy, 0.4062 mGy 그리고 0.0166 mGy로 측정되었다. B그룹의 입사표면선량은 왼쪽유방 상하방향 검사 시 갑상선, 오른쪽 유방, 하복부의 선량이 각각 0.0922 mGy, 0.8575 mGy, 0.0150 mGy로 나타났다. 방호복을 착용한 오른쪽 상하방향 검사는 갑상선이 0.0158 mGy, 왼쪽유방은 0.0286 mGy, 하복부가 0.0173 mGy의 선량을 보여 갑상선과 유방의 선량이 대폭 감소되었고 통계적으로 유의하였다(p<0.05). 모니터의 유선선량을 관찰해 보면 A, B그룹 모두 권고값인 3 mGy 이하의 선량값을 보였다. 본 연구 결과 유방촬영시 환자의 결정장기가 받는 표면선량은 모두 기준치 이하의 선량을 보였으나 방호복 착용에 따른 선량 저감 효과를 볼 수 있어 방호복의 유용성을 확인할 수 있었다. The purpose of this study is to see the usefulness of lead apron for critical organs near the breast under examining. For clinical experiment, 30 female volunteers who agreed to their participation in the experiments, were chosen and divided into two groups, 15 in group A and 15 in group B respectively. group A is to see whether each side of breast under mammography affects to other side glandular on the critical organs is same, because it is not allowed to scan the both breast for same person or to scan repeatedly. Group B is to see the effectiveness of lead apron during the mammography of right breast. Glass dosimeters were placed on the thyroid, the contralateral breast, and lower abdomen where near the breast during examining. The average glandular doses on the surface in mammography of the thyroid gland, the contralateral breast, the lower abdomen were 0.0692 mGy, 0.6790 mGy, and 0.0122 mGy, respectively, which was an extremely low level of glandular dose. In group B, as to the thyroid gland, average dose was decreased from 0.0922 mGy to 0.0158 mGy. The average dose of contralateral breast was decreased from 0.8575 mGy to 0.0286 mGy. The average doses of lower abdomen was decrease 0.0150 mGy to 0.0173 mGy. As to the lower abdomen, dose decreased from 0.0150 mGy before the use of an apron down to 0.0173 mGy after the use. As p-value was under 0.05, statistically significant difference was observed between the two groups. Wearing an apron can have the protective effects on the thyroid gland up to 20 times lower than not wearing one. Besides, it is also necessary to protect the other breast during the examination by wearing one.